The aim of this study is twofold: to investigate the acute and long-term effects of electroconvulsive therapy (ECT) upon certain aspects of brain function; and to determine whether alterations in ECT stimulus waveform or electrode placement modify such effects. It is proposed that brief stimulus ECT applied across unilateral, non-dominant electrodes can be just as therapeutic as more conventional methods utilizing sine wave stimuli and bilateral electrode placement, while producing less psychological side effects - both early and late. Evidence based on published reports will be given to support this contention, and the hypothesis will be tested in a double-blind controlled study in which long-term clinical psychologic, and neurophysiologic results of different methods of ECT will be compared with measurements made before and both two days and six months after a course of treatment. The evaluation parameters to be used will be clinical ratings, anterograde and retrograde memory performance and electroencephalographic (EEG) slow wave activity. Subjects will be sixty hospitalized depressed psychiatric patients referred for ECT and 30 matched control patients who will be treated solely with psychopharmacologic agents and psychotherapy.